let a = 100;
let obj ={
    a:3,
    b:4,
    getA:function (){
        setTimeout(function (){
           console.log(this.a)
        },0)
    },
    getB:function (){
        let b = 10;
        return function (){
            console.log(this.b)
        }
    }
}
obj.getA();
obj.getB()();